The X-ray test was done with eight replications of 25 seeds, placed on double-faced adhesive tape on a transparent plastic sheet; the seeds were numbered according to their position on the sheet , so they could be identified later

Seeds were dried for 1 h, at 25˚C, in a flow hood chamber, and inserted in a sterile Omnitray (Nalge Europe Ltd., Hereford, U.K.) with lid. This dish was placed on a black and white Polapan 52 film and introduced in a Faxitron model MX-20 cabinet

The radiation intensity and exposure time, which permitted the best visualization of the internal fissures of the rice seeds, was 14 kV for 360 seconds, as described by Menezes et al. (2005), using Faxitron MX-20 X-Ray equipment.

The images included in Figure 6, obtained from digital equipment (Faxitron MX-20), permit the detection of differences regarding the area filled by the embryo and show that the X-rays produced by this equipment allowed a more precise evaluation

In this study, we used Helianthus strumosus and Helianthus microcephalus to determine if seed set accurately corresponds with pollen treatments: open pollinated and cross-pollinated flowers would show a higher seed set than self-pollinated and non-pollina